Image recording process, image recording apparatus and liquid composition

ABSTRACT

Disclosed herein is an image recording process for recording an image on a recording medium, which comprises the step of recording the image on the recording medium with an ink, and applying a liquid composition comprising an amphiphilic block copolymer and a solvent to at least one of a region in which the image has been recorded with the ink and a region in which no image is recorded with the ink.

TECHNICAL FIELD

The present invention relates to an image recording process, an imagerecording apparatus and a liquid composition, by which fixing abilityand weather fastness are improved.

BACKGROUND ART

In recent years, digital printing technology has been vigorouslydeveloped. Typical examples of this digital printing technology includethose called electrophotographic technology and ink-jet technology, andimportance of its existence as image-forming technology in homes andoffices has more and more increased in recent years.

Among these, the ink-jet technology has a great feature as a directlyrecording method that it is compact and low in consumption power.Improvement toward higher quality images is also quickly advanced byformation of micro-nozzles, or the like. An example of the ink-jettechnology is a method that an ink fed from an ink tank is heated by aheater in a nozzle to evaporate and bubble the ink, thereby ejecting theink to form an image on a recording medium. Another example is a methodthat an ink is ejected from a nozzle by vibrating a piezoelectricelement.

Since aqueous dye solutions are generally used as inks used in theseink-jet methods, in some cases, bleeding may occur when inks ofdifferent colors overlap with each other, or a phenomenon calledfeathering may appear in a direction of fibers in paper at a recordedportion on a recording medium. Improvement in weather fastness is alsostrongly required because dyes are mainly used as coloring materials. Inorder to improve these problems, an example where a reaction of a dyeink and a pigment ink is used is proposed (U.S. Pat. No. 5,320,668).However, many improvements are still desired.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an image recordingprocess, an image recording apparatus and the like, by which weatherfastness and fixing ability are improved.

The above object can be achieved by the present invention describedbelow.

According to the present invention, there is thus provided an imagerecording process for recording an image on a recording medium, whichcomprises the step of

recording the image on the recording medium with an ink, and

applying a liquid composition comprising an amphiphilic block copolymerand a solvent to at least one of a region in which the image has beenrecorded with the ink and a region in which no image is recorded withthe ink.

The image recording process according to the present invention maycomprise applying the liquid composition comprising the amphiphilicblock copolymer and the solvent to the region in which no image isrecorded with the ink.

The image recording process according to the present invention maycomprise applying the liquid composition comprising the amphiphilicblock copolymer and the solvent to the region in which the image hasbeen recorded with the ink.

In the image recording process according to the present invention, thecritical micelle concentration of the amphiphilic block copolymer may beat most 0.01% by weight.

In the image recording process according to the present invention, theblock copolymer may have a repeating unit structure of polyvinyl ether.

In the image recording process according to the present invention, theparticle diameter of micelle particles formed by the amphiphilic blockpolymer may be at most 100 nm.

In the image recording process according to the present invention, themolecular weight distribution, Mw (weight average molecular weight)/Mn(number average molecular weight), of the amphiphilic block polymer maybe at most 2.0, and the number average molecular weight Mn may be atleast 200.

According to the present invention, there is also provided an imagerecording apparatus for recording an image on a recording medium, whichcomprises an applying means for applying a liquid composition by causingenergy to act on an ink composition and a liquid composition comprisingan amphiphilic block copolymer and a solvent, and a driving means fordriving the applying means.

According to the present invention, there is further provided a liquidcomposition suitable for use in the image recording process and imagerecording apparatus according to the present invention, which comprisesan amphiphilic block copolymer and a solvent.

The liquid composition according to the present invention may contain nocoloring material.

According to the present invention, there can be provided an imageforming process, by which image-recording properties such as weatherfastness, fixing ability and glossiness are improved, and an apparatusand a liquid composition, which are used in this process.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram illustrating the composition of an in ink-jetrecording apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

1. Ink-Jet Recording Method

With respect to the image recording process according to the presentinvention, a publicly known method may be partially utilized. In thisspecification, an ink-jet recording method, which is a preferredembodiment of the present invention, is described. However, the presentinvention is not limited thereto.

The recording process of the present invention will be described.

The process of the present invention is an image recording process usingan ink-jet recording method. The ink-jet recording process comprisesrecording an image on a recording medium with an ink and then ejectingand applying a liquid composition comprising an amphiphilic blockcopolymer and a solvent and containing no coloring material.

In the ink-jet recording process, the liquid composition comprising theamphiphilic block copolymer and the solvent may be ejected and appliedafter or before the image is recorded on the recording medium with theink.

The ink-jet recording process and apparatus will be first described.

With respect to an ink-jet recording system and apparatus, thosepublicly known may be used without particular limitation. The ink-jetrecording apparatus and recording process will hereinafter beschematically described with reference to FIG. 1. However, theconstruction shown in FIG. 1 is taken as an example, and the presentinvention is not limited thereby.

FIG. 1 is a block diagram illustrating the composition of an in ink-jetrecording apparatus 20. FIG. 1 illustrates a case where a head is movedto record an image on a recording medium. In FIG. 1, to CPU 50 forcontrolling the overall operation of the recording apparatus, anX-direction drive motor 56 and a Y-direction drive motor 58 for drivinga head 70 to X and Y directions, respectively, are connected through anX-motor drive circuit 52 and a Y-motor drive circuit 54, respectively.The X-direction drive motor 56 and Y-direction drive motor 58 are driventhrough the X-motor drive circuit 52 and Y-motor drive circuit 54according to indication by the CPU to determine a position of the head70 to the recording medium. As shown in FIG. 1, a head drive circuit 60is connected to the head 70 in addition to the X-direction drive motor56 and Y-direction drive motor 58. The CPU 50 controls the head drivecircuit 60 to drive the head 70, i.e., to eject an ink-jet ink. Further,an X-encoder 62 and a Y-encoder 64 for detecting the position of thehead 70 are connected to the CPU 50 to input positional information ofthe head 70. A control program is stored in a program memory 66. The CPU50 moves the head 70 on the basis of this control program and thepositional information from the X-encoder 62 and Y-encoder 64 to arrangethe head at a desired position on the recording medium for ejecting theink-jet ink. A desired image can be drawn on the recording medium insuch a manner. In the case of an image recording apparatus that can beequipped with a plurality of ink-jet inks, predetermined times of theabove-described operation are performed, and thereby a desired image canbe drawn on the recording medium.

After the ink-jet ink is ejected, the head 70 may also be moved to aposition where a removing means (not illustrated) for removing anexcessive ink attached to the head is arranged, as needed, to clean thehead by wiping or the like. As a specific method for cleaning the head,any conventional method may be used as it is.

After the drawing of the image is completed, the recording medium, onwhich the image has been drawn, is replaced with a new recording mediumby a recording medium-conveying mechanism (not illustrated).

In the present invention, the above-described embodiment may be modifiedor changed within limits not departing from the subject matter thereof.For example, the head 70 may be moved only to the X direction (or Ydirection), and the recording medium may be moved to the Y direction (orX direction) to draw an image while interlocking these movements thoughthe example where the head 70 is moved to both X and Y directions hasbeen described in the above-described embodiment.

In the present invention, a head equipped with a means (for example,electrothermal converter or laser beam) for generating thermal energy asenergy used for ejecting the ink-jet ink and ejecting the ink-jet ink bythe thermal energy brings about an excellent effect. High definition ofthe drawing can be achieved according to such a system. Far excellentdrawing can be made by using the ink composition for ink-jet of thepresent invention.

With respect to the typical construction and principle of the apparatusequipped with the means for generating the thermal energy, those usingthe basic principle disclosed in, for example, U.S. Pat. Nos. 4,723,129and 4,740,796 are preferred. This system may be applied to any of theso-called On-Demand type and continuous type. In particular, theOn-Demand type is effective because at least one driving signal whichcorresponds to recording information and gives a rapid temperature riseexceeding nuclear boiling is applied to an electrothermal converterarranged corresponding to a liquid path, in which a liquid is retained,thereby causing the electrothermal converter to generate thermal energyto cause film boiling on the heat-acting surface of a head, so that abubble can be formed in the liquid in response to the driving signal inrelation of one to one. The liquid is ejected through an ejectionopening by the growth and contraction of this bubble to form at leastone droplet. When the driving signal is applied in the form of a pulse,the growth/contraction of the bubble is suitably conducted in a moment,so that the ejection of the liquid, which is excellent in responsivenessin particular, can be achieved. It is therefore preferable to use suchpulsed signals. As the pulsed driving signal, such signals as describedin U.S. Pat. Nos. 4,463,359 and 4,345,262 are suitable. When theconditions described in U.S. Pat. No. 4,313,124 that discloses aninvention relating to the rate of temperature rise on the heat-actingsurface are adopted, far excellent ejection can be conducted.

As the construction of the head, such combined constructions (linearliquid flow path or perpendicular liquid flow path) of ejectionopenings, a liquid flow path and electrothermal converters as disclosedin the above-described publications, and besides constructions based onU.S. Pat. Nos. 4,558,333 and 4,459,600 which disclose the constructionthat a heat-acting portion is arranged in a curved region may also beincluded in the present invention. In addition, constructions based onJapanese Patent Application Laid-Open No. S59-123670 which discloses theconstruction that a slit common to a plurality of electrothermalconverters is used as an ejection part of the electrothermal converters,and Japanese Patent Application Laid-Open No. S59-138461 which disclosesthe construction that an opening which absorbs pressure wave of thermalenergy is provided in opposition to an ejection part may also beeffective for the present invention. Namely, the ejection of the ink-jetink can be surely and efficiently conducted according to the presentinvention even if the head is in any form.

Further, the present invention may also be applied to a full-line typehead having a length corresponding to the longest width of recordingmedia. Both construction that the length is satisfied by a combinationof plural recording heads and construction of one head integrally formedmay be used as such a head.

In addition, the present invention is effective even when among those ofthe serial type, a head fixed to an apparatus body, or a replaceablechip type head in which electrical connection to the apparatus body andfeed of an ink from the apparatus body become feasible by beinginstalled in the apparatus body is used.

Further, the apparatus according to the present invention mayadditionally have a droplet-removing means. When such a means isequipped, far excellent ejecting effect can be realized.

Moreover, the addition of preliminary auxiliary means, etc., asconstitution of the apparatus according to the present invention ispreferred because the effects of the present invention can be morestabilized. As specific examples thereof, may be mentioned capping meansfor the head, pressurizing or sucking means, preliminary heating meansfor conducting heating by electrothermal converters, other heatingelements than these or combinations thereof, and preliminary ejectingmeans for conducting other ejections than ejection of an ink.

In the present invention, it is most effective to perform theabove-described film boiling system.

In the apparatus according to the present invention, the amount of theink-jet ink ejected from each ejection opening of the ejection head ispreferably within a range of from 0.1 pl to 100 pl.

The ink composition of the present invention may also be used in anindirect recording apparatus using, for example, a recording system thatan image is formed on an intermediate transfer medium with an ink, andthe image is then transferred to a recording medium such as paper.Further, it may be used in an apparatus using an intermediate transfermedium by a direct recording system.

2. Ink Composition

Suitable ink compositions are used for such ink-jet recording processand apparatus as described above, and recording, printing or drawing isconducted by any publicly known method. A coloring material, a solventand additives are generally contained in the ink compositions. Examplesthereof are shown below.

(Coloring Material)

A coloring material such as a pigment or a dye is contained in the inkcompositions of the present invention. Any publicly known coloringmaterial may be used as this coloring material.

Specific examples of pigments and dyes used in the ink compositions arementioned below.

The pigment may be either an organic pigment or an inorganic pigment. Aspigments used in inks, may be used black pigments and pigments of threeprimary colors of cyan, magenta and yellow. Incidentally, other colorpigments than those described above, colorless or light-colored pigmentsand metalescent pigments may also be used. In the present invention,newly synthesized pigments may also be used.

Examples of commercially available pigments in black, cyan, magenta andyellow are mentioned below.

As examples of black pigments, may be mentioned Raven 1060, Raven 1080,Raven 1170, Raven 1200, Raven 1250, Raven 1255, Raven 1500, Raven 2000,Raven 3500, Raven 5250, Raven 5750, Raven 7000, Raven 5000 ULTRA II andRaven 1190 ULTRA II (all, products of Columbian Carbon Co.), BlackPearls L, MOGUL-L, Regal 400R, Regal 660R, Regal 330R, Monarch 800,Monarch 880, Monarch 900, Monarch 1000, Monarch 1300 and Monarch 1400(all, products of Cabot Company), Color Black FW1, Color Black FW2,Color Black FW200, Color Black 18, Color Black S160, Color Black S170,Special Black 4, Special Black 4A, Special Black 6, Printex 35, PrintexU, Printex 140U, Printex V and Printex 140V (all, products of DegussaAG), and No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, No. 2300,MCF-88, MA600, MA7, MA8 and MA100 (all, products of Mitsubishi ChemicalCorporation). However, usable black pigments are not limited thereto.

As examples of cyan pigments, may be mentioned C.I. Pigment Blue 1, C.I.Pigment Blue 2, C.I. Pigment Blue 3, C.I. Pigment Blue 15, C.I. PigmentBlue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. PigmentBlue 16, C.I. Pigment Blue 22 and C.I. Pigment Blue 60. However, usablecyan pigments are not limited thereto.

As examples of magenta pigments, may be mentioned C.I. Pigment Red 5,C.I. Pigment Red 7, C.I. Pigment Red 12, C.I. Pigment Red 48, C.I.Pigment Red 48:1, C.I. Pigment Red 57, C.I. Pigment Red 112, C.I.Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 146, C.I.Pigment Red 168, C.I. Pigment Red 184, C.I. Pigment Red 202 and C.I.Pigment Red 207 (all, trade names). However, usable magenta pigments arenot limited thereto.

As examples of yellow pigments, may be mentioned C.I. Pigment Yellow 12,C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I. Pigment Yellow 16,C.I. Pigment Yellow 17, C.I. Pigment Yellow 74, C.I. Pigment Yellow 83,C.I. Pigment Yellow 93, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97,C.I. Pigment Yellow 98, C.I. Pigment Yellow 114, C.I. Pigment Yellow128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 151 and C.I. PigmentYellow 154 (all, trade names). However, usable yellow pigments are notlimited thereto.

Pigments which can be self-dispersed in water may also be used. Thepigments which can be self-dispersed in water include those utilizingsteric hindrance that a polymer is adsorbed on the surface of a pigment,and those utilizing electrostatic repulsion force. Examples ofcommercially available products thereof include CAB-O-JET 200 andCAB-O-JET 300 (both, products of Cabot Company), and Microjet Black CW-1(product of Orient Chemical Industries Ltd.).

When the pigment is used in the ink composition, the amount of thepigment is preferably from 0.1 to 50% by weight based on the weight ofthe ink composition. If the amount is less than 0.1% by weight,sufficient image density may not be achieved in some cases. If theamount exceeds 50% by weight, the fixing ability of an image formed maybe deteriorated in some cases. A more preferable range of the amount isfrom 0.5% by weight to 30% by weight.

A dye may also be used in place of or in combination of the pigment.Such water-soluble dyes as direct dyes, acid dyes, basic dyes, reactivedyes and food dyes, and insoluble colorants such as disperse dyes, asdescribed below, may be used. As examples of oil-soluble dyes, may bementioned C.I. Solvent Blue 33, 38, 42, 53, 65, 67, 70, 104, 114, 115and 135; C.I. Solvent Red 25, 31, 86, 92, 97, 118, 132, 160, 186, 187and 219; and C.I. Solvent Yellow 1, 49, 62, 74, 79, 82, 83, 89, 90, 120,121, 151, 153 and 154 (all, trade names).

As examples of water-soluble dyes, may be mentioned

direct dyes such as C.I. Direct Black 17, 62 and 154; C.I. Direct Yellow12, 87 and 142; C.I. Direct Red 1, 62 and 243; C.I. Direct Blue 6, 78and 199; C.I. Direct Orange 34 and 60; C.I. Direct Violet 47 and 48;C.I. Direct Brown 109; and C.I. Direct green 59 (all, trade names),

acid dyes such as C.I. Acid Black 2, 52 and 208; C.I. Acid Yellow 11, 29and 71; C.I. Acid Red 1, 52 and 317; C.I. Acid Blue 9, 93 and 254; C.I.Acid Orange 7 and 19; and C.I. Acid Violet 49 (all, trade names),

reactive dyes such as C.I. Reactive Black 1, 23 and 39; C.I. ReactiveYellow 2, 77 and 163; C.I. Reactive Red 3, 111 and 221; C.I. ReactiveBlue 2, 101 and 217; C.I. Reactive Orange 5, 74 and 99; C.I. ReactiveViolet 1, 24 and 38; C.I. Reactive Green 5, 15 and 23; and C.I. ReactiveBrown 2, 18 and 33 (all, trade names), and

C.I. Basic Black 2; C.I. Basic Red 1, 12 and 27; C.I. Basic Blue 1 and24; C.I. Basic Violet 7, 14 and 27; and C.I. Food Black 1 and 2 (all,trade names).

When the dye is used in the ink composition, the amount of the dye ispreferably from 0.1 to 50% by weight based on the weight of the inkcomposition.

(Additives)

Various additives and aids may be added to the ink composition asneeded. A dispersion stabilizer for dispersing a pigment in a solvent isone of the additives. When dispersion is insufficient, anotherdispersion stabilizer may also be added.

A resin having both hydrophilic part and hydrophobic part or asurfactant may be used as another dispersion stabilizer. Examples of theresin having both hydrophilic part and hydrophobic part includecopolymers of a hydrophilic monomer and a hydrophobic monomer.

Examples of the hydrophilic monomer include acrylic acid, methacrylicacid, maleic acid, fumaric acid, monoesters of the carboxylic acidsdescribed above, vinyl alcohol and acrylamide. Examples of thehydrophobic monomer include styrene, styrene derivatives such asα-methylstyrene, vinylcyclohexane, vinylnaphthalene derivatives, acrylicacid esters and methacrylic acid esters. Any of those of various formssuch as random, block and graft copolymers may be used as the copolymer.It goes without saying that both hydrophilic monomer and hydrophobicmonomer are not limited to those described above.

An anionic, nonionic, cationic or amphoteric surfactant may be used asthe surfactant.

Examples of the anionic surfactant include fatty acid salts, alkylsulfate salts, alkylarylsulfonic acid salts, alkyl diaryl etherdisulfonic acid salts, dialkylsulfosuccinic acid salts, alkylphosphonicacid salts, naphthalenesulfonic acid-formalin condensates,polyoxyethylene alkylphosphate salts and glycerol borate fatty acidesters.

Examples of the nonionic surfactant include polyoxyethylene alkylethers, polyoxyethylene-oxypropylene block copolymers, sorbitan fattyacid esters, glycerol fatty acid esters, polyoxyethylene fatty acidesters, polyoxyethylenealkylamines, fluorine-containing surfactants andsilicon-containing surfactants.

Examples of the cationic surfactant include alkylamine salts, quaternaryammonium salts, alkylpyridinium salts and alkylimidazolinium salts.

Examples of the amphoteric surfactant include alkylbetaines, alkylamineoxides and phosphatidyl choline.

Incidentally, the surfactants are also not limited to those mentionedabove.

Besides, a hydrophilic solvent may be added as needed. When theresulting ink composition is used as an ink-jet ink in particular, thehydrophilic solvent is used for the purpose of preventing drying atorifices of the ink and solidification of the ink. Water alone or amixture of water and the hydrophilic solvent may be used as a solvent.

As the hydrophilic solvent, any of those described above may be used asit is. The content thereof is within a range of from 0.1 to 60% byweight, preferably from 1 to 40% by weight based on the whole weight ofthe ink.

Examples of other additives that can be added to the ink include pHadjustors for achieving stabilization of the ink and stability of theink to piping in a recording apparatus; penetrants for acceleratingpenetration of the ink into a recording medium to facilitate apparentdrying; mildewproofing agents for preventing occurrence of mildew in theink; chelating agents for blocking metal ions in the ink to preventdeposition of metals at a nozzle portion and deposition of insolublematter in the ink; antifoaming agents for preventing occurrence of foamduring circulation, transferring or preparation of the ink;antioxidants; viscosity modifiers; conductivity-imparting agents; andultraviolet absorbents.

Any other component than those described above may be contained in theink composition. The ink composition can be prepared by, for example,mixing the above-described components, and uniformly dissolving ordispersing them. For example, the ink composition may be prepared byuniformly mixing a plurality of components in a common solvent,inverting the resultant mixture to a water phase or a non-aqueous phase,dispersing the inverted mixture by a sand mill, ball mill, homogenizeror nanomizer to prepare an ink mother liquor and adding a solvent andadditives to this mother liquor to adjust physical properties.

3. Liquid Composition Containing an Amphiphilic Block Copolymer and aSolvent

First, the present invention relates to an ink-jet recording processcomprising recording an image with the ink composition described aboveand then ejecting and applying a liquid composition comprising anamphiphilic block copolymer and a solvent and containing no coloringmaterial. The block copolymer is also called a block polymer. Morespecifically, the process is a process in which the liquid compositioncomprising the amphiphilic block copolymer and the solvent andcontaining no coloring material is applied on to a recording medium, onwhich the image has been recorded with the ink composition containing acoloring material. As a result, a layer of the amphiphilic blockcopolymer is formed on the surface of the coloring material. The liquidcomposition comprising the amphiphilic block copolymer and the solventand containing no coloring material may be applied in whole orpartially. The polymer layer formed by the amphiphilic block copolymermay be uniform or non-uniform, or intermittent.

In the present invention, the polymer layer of the amphiphilic blockcopolymer formed by the liquid composition comprising the amphiphilicblock copolymer and the solvent and containing no coloring material canexhibit functions of protecting the coloring material from externalenvironment. One of them is a function of improving the weather fastnessof an image recorded, and another is a function of improving the fixingability of the coloring material to a recording medium, such as rub-offresistance.

An embodiment of the present invention resides in that the blockcopolymer is a polymer which forms polymer micelles. A block copolymerwhich shows a molecule-dissolved state as little as possible, ispreferred. More specifically, its critical micelle concentration ispreferably at most 0.01% by weight. The critical micelle concentrationis more preferably at most 0.001% by weight. The micelle concentrationcan be determined by observing a critical concentration of a polymer, atwhich a solvophobic substance is dispersed, or likewise observing acritical concentration of a polymer, at which micelle particles areformed, by dynamic light scattering. Those having a relatively highmolecular weight of their solvophobic segment are preferred, which showas little molecularly dissolved polymers as possible, and which arepreferred for forming polymer micelles. More specifically, it ispreferable that the number of repeating units be at least 20, and thenumber average molecular weight be at least 5,000. It is more preferablethat the number of repeating units be at least 40, and the numberaverage molecular weight be at least 8,000. The number average molecularweight can be measured by gel permeation chromatography.

The block copolymer that is a component characteristically used in thepresent invention will now be described. Specific examples thereofinclude acrylic or methacrylic block polymers, block copolymers composedof polystyrene and another addition polymerization system orcondensation polymerization system, and block copolymers having blocksof polyoxyethylene and polyoxyalkylene. Any of well known blockcopolymers such as sodium polystyrene acrylate, copolymers of methylmethacrylate and potassium acrylate, and polystyrene polyethylene glycolmay be used. The block copolymer is more preferably in a block form ofAB, ABA, ABD or the like, in which A, B and D indicate block segmentsdifferent from one another.

No particular limitation is imposed on the ratio of an amphiphilicblock. However, it is preferably from 1:100 to 100:1, more preferablyfrom 1:9 to 9:1 in terms of a molar ratio.

In the present invention, the block polymer may be a graft polymerbonded in a T-shaped form to a certain polymer chain. Each segment ofthe block copolymer may be a copolymer segment, and the copolymer formthereof may be, for example, a random segment or graduation segment.

In the present invention, a polymer having a low glass transition pointis preferably used from the viewpoint of adhesion to a recording medium.Such a polymer is a polymer having a glass transition temperature ofpreferably at most 25° C., more preferably at most 0° C.

In the present invention, a block copolymer containing a polyalkenylether structure is preferably used. A block copolymer composed ofpolyalkenyl ether generally has a low glass transition temperature. Theglass transition temperature may amount to −20° C. or lower in somecases. Therefore, such a block copolymer is preferably used. A blockcopolymer containing a polyvinyl ether structure is particularlypreferred. A block copolymer composed of the polyvinyl ether structureis preferably used because it generally has a low glass transitiontemperature and from the viewpoints of the critical micelleconcentration and development of good amphiphilic property in that aminute block copolymer is formed by using a polymerization process,which will be described subsequently. Many synthesizing processes for a(co)polymer containing a polyalkenyl ether structure preferably used inthe present invention have been reported (for example, Japanese PatentApplication Laid-Open No. H11-080221). A process by cationic livingpolymerization by Aoshima (Japanese Patent Application Laid-Open Nos.H11-322942 and H11-322866), et al. is representative thereof. Byconducting polymer synthesis by the cationic living polymerization,various polymers such as homopolymers, copolymers composed of two ormore monomers, block polymers, graft polymers and graduation polymerscan be synthesized with their chain lengths (molecular weights) exactlymade uniform. Further, in the polyalkenyl ether, various functionalgroups can be introduced into side chains thereof. Besides, the cationicpolymerization process may be conducted in an HI/I₂ system, HCl/SnCl₄system or the like.

The structure of the block polymer containing the polyalkenyl etherstructure may be a copolymer composed of vinyl ether and anotherpolymer. However, a block copolymer composed of the polyalkenyl ether orpolyvinyl ether structure is preferred.

The block polymer containing the polyvinyl ether structure preferablyused in the present invention preferably has a repeating unit structurerepresented by the following general formula (1)—(CH₂—CH (OR¹))   (1)wherein R¹ is selected from a linear, branched or cyclic alkyl grouphaving 1 to 18 carbon atoms, —(CH(R²)—CH(R³)—O)₁—R⁴ and—(CH₂)_(m)—(O)_(n)—R⁴, in which m is an integer of from 1 to 12, n is 1or 0, R² and R³ are, independently of each other, hydrogen or CH₃, andR⁴ is a linear, branched or cyclic alkyl group having 1 to 6 carbonatoms, Ph, Pyr, Ph-Ph, Ph-Pyr, —CHO, —CH₂CHO, —CO-CH═CH₂, —CO—C(CH₃)═CH₂ or —CH₂COOR⁵, with the proviso that hydrogen bonded to carbonmay be substituted by a linear or branched alkyl group having 1 to 4carbon atoms, F, Cl or Br, and carbon in the aromatic ring may besubstituted by nitrogen, and R⁵ is an alkyl group having 1 to 5 carbonatoms.

In the present invention, -Ph, -Pyr, -Ph-Ph and -Ph-Pyr denote phenyl,pyridyl, biphenyl and pyridylphenyl groups, respectively. With respectto the pyridyl, biphenyl and pyridylphenyl groups, they may be anyposition isomers.

In the present invention, the amphiphilic block copolymer is used. Sucha block copolymer can be obtained by, for example, selecting asolvophobic block segment and a solvophilic block segment from therepeating unit structures of the general formulae (1) and synthesizingthem. In the case of the graft polymer, an amphiphilic polymer can beobtained by, for example, grafting a hydrophobic polymer segment on asolvophilic polymer. Water is an example of a preferable medium.

The molecular weight distribution Mw (weight average molecularweight)/Mn (number average molecular weight) of the block polymer usedin the present invention is preferably at most 2.0, more preferably atmost 1.6, still more preferably at most 1.3.

The number average molecular weight Mn of the block polymer used in thepresent invention is preferably at least 200, preferably at least 3,000,but preferably does not exceed 1,000,000. If the number averagemolecular weight is lower than 200, the dispersion stability of afunctional substance may be deteriorated in some cases. In the presentinvention, the number average molecular weight and weight averagemolecular weight of a polymer can be measured by volume exclusionchromatography (another name: gel permeation chromatography (GPC)). Thecontent of the block copolymer used in the composition according to thepresent invention is from 0.1% by weight to 90% by weight, preferablyfrom 1% by weight to 50% by weight based on the weight of thecomposition according to the present invention. If the content is lowerthan 0.1% by weight, the functional substance may not be sufficientlydispersed in some cases. If the content exceeds 90% by weight, theviscosity of the resulting composition may become too high in somecases.

In the present invention, the amphiphilic block copolymer ischaracteristically used. In the present invention, the amphiphilic blockcopolymer may preferably form micelles. By forming the micelle, arelatively low viscosity suitable for ink-jet ejection can be realizedat a certain polymer concentration. The water resistance of a recordingmedium may also be improved by the hydrophobic segment.

The size of micelle particles formed from the amphiphilic blockcopolymer is preferably 100 nm or less. Excessively large particle sizesmay lead to excessively high viscosity of the composition in some cases.

The composition according to the present invention contains a solvent.No particular limitation is imposed on the solvent contained in thecomposition according to the present invention. The solvent means amedium that can dissolve, suspend or disperse components contained inthe ink composition therein. In the present invention, organic solventssuch as various kinds of linear, branched and cyclic aliphatichydrocarbons, aromatic hydrocarbons, and heterocyclic aromatichydrocarbons, hydrophilic solvents, water, and the like may be used asthe solvent. It goes without saying that mixed solvents thereof may alsobe used.

In particular, water and hydrophilic solvents may be suitably used inthe composition according to the present invention.

Examples of the hydrophilic solvents include polyhydric alcohols such asethylene glycol, diethylene glycol, triethylene glycol, polyethyleneglycol, propylene glycol, polypropylene glycol and glycerol, ethers ofpolyhydric alcohols, such as ethylene glycol monomethyl ether, ethyleneglycol monoethyl ether, ethylene glycol monobutyl ether, diethyleneglycol monoethyl ether and diethylene glycol monobutyl ether, andnitrogen-containing solvents such as N-methyl-2-pyrrolidone, substitutedpyrrolidone and triethanolamine. Monohydric alcohols such as methanol,ethanol and isopropanol may also be used. With respect to the pH ofwater, the composition may be used in an overall pH range. However, thepH is preferably from 1 to 14. The content of the solvent used in thepresent invention is from 1% by weight to 99% by weight, preferably from10% by weight to 99% by weight. If the content is lower than 1% byweight, the viscosity of the resulting composition may become too highin some cases. If the content exceeds 99% by weight, the function of thefunctional substance may not be sufficiently exhibited in some cases.

Besides the above components, additives such as antioxidants, viscosityreducing agents, ultraviolet absorbents, surfactants and mildewproofingagents may be added to the composition according to the presentinvention the present invention.

Second, the present invention relates to an ink-jet recording apparatus.The apparatus illustrated in FIG. 1 may be mentioned as a specificexample thereof. The apparatus can be applied to various ink-jetrecording apparatus such as a piezo ink-jet system using a piezoelectricelement and a thermal ink-jet system that thermal energy is applied toan ink to bubble the ink.

The present invention will hereinafter be described in detail by thefollowing examples. However, the present invention is not limited tothese examples.

EXAMPLE 1

An ink-jet printer (BJC-600, trade name, manufactured by Canon Inc.) wasused to make tests. After printing was conducted with a magenta ink, thefollowing block polymer (AB block polymer composed of isobutyl vinylether (IBVE; block A component) and sodium 4-(2-vinyloxyethoxy)benzoate(block B component); polymerization ratio A/B=200/30; number averagemolecular weight: 35,000, weight average molecular weight: 43,200(identified by means of NMR and GPC)) was used to add 5 parts by mass ofthe block polymer and 15 parts by mass of diethylene glycol to 250 partsby mass of ion-exchanged water. The pH of the resultant mixture wasadjusted to 9, and the mixture was subjected to a dispersion treatmentby means of an ultrasonic homogenizer. The thus-treated mixture wasfiltered under pressure through a filter having a pore size of 1 μm. Acomposition thus prepared was charged into a vacant ink tank, andprinting was conducted to overprint the same pattern as that of themagenta ink thereon. The viscosity of this composition was measured by aviscoelastometer manufactured by Rheologica Co. and was found to be 3.9cp.

After 5 minutes elapsed from the printing, the printed area was stronglyrubbed twice with a line marker. As a result, no smeared image trailingedge of the magenta color appeared. The retention of optical density(OD) of the printed area after 1 week was 98.2%.

After 3 minutes from the recording, 10 cc of distilled water was droppedon the recording medium. As a result, no bleeding occurred.

The block polymer composition was diluted in such a manner that theconcentration of the block polymer amounts to 0.0005% by weight, andformation of particles was observed by means of a dynamiclight-scattering apparatus (DLS-7000, trade name; manufactured by OtsukaElectronics Co., Ltd.). As a result, polymer micelles having an averageparticle diameter of 94 nm was observed. At the same time, its criticalmicelle concentration both in water and the above mixed solvent wasfound to be 0.0005% by weight or lower.

EXAMPLE 2

The polymer used in EXAMPLE 1 was changed to an AB block polymer(polymerization ratio A/B=100/30; number average molecular weight:15,000, weight average molecular weight: 22,200 (identified by means ofNMR and GPC)) composed of a 50:50 random copolymer (block A segment) of(2-biphenyloxyethyl vinyl ether and isobutyl vinyl ether and sodium4-(2-vinyloxyethoxy)benzoate (block B segment) to make the same test asin EXAMPLE 1. After 5 minutes elapsed from the printing, the printedarea was strongly rubbed twice with a line marker. As a result, nosmeared image trailing edge of the magenta color appeared. The retentionof optical density (OD) of the printed area after 1 week was 97.5%.

The block polymer composition was diluted in such a manner that theconcentration of the block polymer amounts to 0.0005% by weight, andformation of particles was observed by means of a dynamiclight-scattering apparatus (DLS-7000, trade name; manufactured by OtsukaElectronics Co., Ltd.). As a result, polymer micelles having an averageparticle diameter of 64 nm was observed. At the same time, its criticalmicelle concentration both in water and the above mixed solvent wasfound to be 0.0005% by weight or lower.

COMPARATIVE EXAMPLE 1

The test by the ink-jet printer BJC-600 in EXAMPLE 1 was made exceptthat the block polymer composition was not applied after the printingwith the magenta ink. After 5 minutes elapsed from the printing, theprinted area was strongly rubbed twice with a line marker. As a result,a smeared image trailing edge of the magenta color appeared. Theretention of optical density (OD) of the printed area after 1 week was88.1%.

COMPARATIVE EXAMPLE 2

Polyvinyl alcohol, which was a water-soluble polymer and had a numberaverage molecular weight of 15,000, was used in place of the amphiphilicblock copolymer to prepare a composition to be applied after therecording with the ink. The viscosity of this composition was measuredby a viscoelastometer manufactured by Rheologica Co. and was found to be36.9 cp. The polymer concentration was seven times diluted to adjust thecomposition. As a result, the viscosity thereof was 6.2 cp. Thecomposition was charged into a vacant ink tank after conductingrecording in the same manner as in EXAMPLE 1, and printing was conductedto overprint the same pattern as that of the magenta ink thereon. After3 minutes from the recording, 10 cc of distilled water was dropped onthe recording medium. As a result, bleeding occurred intensely.

EXAMPLE 3

Five parts by weight of the block copolymer used in EXAMPLE 1 and 3parts by weight of Pigment Blue 15:3 were dispersed in 20 parts byweight of DMF by means of an ultrasonic dispersing device, and 70 partsby weight of purified water was gradually added to obtain a dispersionof the cyan pigment. To this dispersion were added 15 parts by weight ofdiethylene glycol and 5 parts by weight of glycerol, thereby preparingan ink composition. This cyan ink was used to record on glossy paperPR101 (trade name, product of Canon Inc.) a vertical line pattern havinga line width of 2 mm with a space of 2 mm between lines in an 8-cmsquare by means of the same ink-jet printer as that used in EXAMPLE 1.The composition used in EXAMPLE 1, which contained no coloring materialand contained the block copolymer, was applied to all space portions 2mm wide in the 8-cm square where no cyan ink was applied. The gloss ofthe print thus obtained was measured from a direction of 20° withrespect to the direction of the vertical lines by means of a glossmeter. The measurement was conducted at 50 points while shifting therecording medium 1 mm by 1 mm. As a result, a difference of the glossvalues were within 7%.

COMPARATIVE EXAMPLE 3

Five parts by weight of the block copolymer used in EXAMPLE 1 and 3parts by weight of Pigment Blue 15:3 were dispersed in 20 parts byweight of DMF by means of an ultrasonic dispersing device, and 70 partsby weight of purified water was gradually added to obtain a dispersionof the cyan pigment. To this dispersion were added 15 parts by weight ofdiethylene glycol and 5 parts by weight of glycerol, thereby preparingan ink composition. This cyan ink was used to record on glossy paperPR101 (trade name, product of Canon Inc.) a vertical line pattern havinga line width of 2 mm with a space of 2 mm between lines in an 8-cmsquare by means of the same ink-jet printer as that used in EXAMPLE 1.The recording medium was shifted by 1 mm to measure gloss at each onepoint of a portion where the cyan ink was applied and a portion where nocyan ink was applied. A difference between their gloss values was 32%.

This application claims priorities from Japanese Patent Applictions No.2003-335855 filed on Sep. 26, 2003 and No. 2004-266981 filed on Sep. 14,2004, which are hereby incorporated by reference herein.

1. An image recording process for recording an image on a recordingmedium, which comprises the step of: recording the image on therecording medium with an ink; and applying a liquid compositioncomprising an amphiphilic block copolymer and a solvent to at least oneof a region, in which the image has been recorded with the ink and aregion in which no image is recorded with the ink.
 2. The imagerecording process according to claim 1, wherein the liquid compositioncomprising the amphiphilic block copolymer and the solvent is applied tothe region in which no image is recorded with the ink.
 3. The imagerecording process according to claim 1, wherein the liquid compositioncomprising the amphiphilic block copolymer and the solvent is applied tothe region in which the image has been recorded with the ink.
 4. Theimage recording process according to claim 1, wherein the amphiphilicblock copolymer has a critical micelle concentration of at most 0.01% byweight.
 5. The image recording process according to claim 1, wherein theblock copolymer has a repeating unit structure of polyvinyl ether. 6.The image recording process according to claim 1, wherein theamphiphilic block polymer forms micelle particles having a particlediameter of at most 100 nm.
 7. The image recording process according toclaim 1, wherein the amphiphilic block polymer has a molecular weightdistribution Mw (weight average molecular weight)/Mn (number averagemolecular weight) of at most 2.0.
 8. The image recording processaccording to claim 1, wherein the number average molecular weight Mn isat least
 200. 9. An image recording apparatus for recording an image ona recording medium, which comprises an applying means for applying aliquid composition by causing energy to act on an ink composition and aliquid composition comprising an amphiphilic block copolymer and asolvent, and a driving means for driving the applying means.
 10. Aliquid composition suitable for use in the image recording processaccording to claim 1, which comprises an amphiphilic block copolymer anda solvent.
 11. The liquid composition according to claim 10, whichcontains no coloring material.
 12. A liquid composition suitable for usein the image recording apparatus according to claim 9, which comprisesan amphiphilic block copolymer and a solvent.
 13. The liquid compositionaccording to claim 12, which contains no coloring material.